Headaches on the left side of the head can be caused by migraines, minor injuries, ear infections, or even dental problems. In some cases, they may also signal conditions affecting blood vessels, the eyes, or the jaw.

Although many causes of headaches on the left side of the head are not serious, some situations may require urgent medical care. Warning signs include sudden severe pain, vision loss, weakness, or seizures.

Headaches on the left side of the head can last for minutes or even days, depending on the cause. They may improve with rest and simple treatments, but persistent or severe cases often require medical evaluation and targeted care.

What does a left-sided headache mean?

Headaches on the left side of the head can be caused by:

1. Blows and injuries

A headache on the left side of the head can occur due to blows and injuries that occur in the area from an accident, like a fall, a ball to the head or a car accident. With very mild blows, other symptoms do not tend to emerge, other than some pain and mild swelling, which resolves within a few days.

However, a more significant head injury on the left side of the head can cause a concussion. Read more about the symptoms of a concussion and how it can present.

What it feels like: This type of headache is often described as a throbbing or pressure sensation, with pain mostly felt in the area that underwent trauma.

How to treat: This type of headache tends to improve within a few days. However, if the pain is intense or persists for more than a week, you should see a doctor, who may recommend analgesics like acetaminophen.

If you also experience symptoms like vomiting, seizures or loss of consciousness immediately after the injury, you should proceed to an emergency room for a more thorough assessment to rule out a serious brain injury.

2. Migraine

A migraine can cause a left side headache. Generally, migraine pain worsens with physical activity, like walking or going up stairs. It can emerge with other symptoms like vomiting, nausea, blurry vision and light flashes, which can occur before or during the headache. Learn more about migraine symptoms and how they can present.

What it feels like: Migraine is usually throbbing or pulsating and felt just on one side of the head.

How to treat: If you experience a migraine, you should see a doctor or neurologist for evaluation and treatment as necessary. Treatment may involve medications, like analgesics and anticonvulsants, and lifestyle changes, like sleeping, ensuring adequate sleep routines and regular exercise. A migraine diet may also be beneficial for reducing symptoms and preventing flare-ups.

3. CNS vasculitis

Headaches on the left side of the head can be caused by vasculitis, or specifically CNS vasculitis, which is characterized by swelling of arteries and veins in the brain and spine. Generally speaking, these blood vessels are protected by the blood-brain barrier, however swelling can occur if the immune system is activated to protect these vessels from a foreign antigen.

The antigen causing swelling is not easily identifiable or well-understood. It is hypothesized the CNS vasculitis may be triggered by an allergic drug reaction or by severe cocaine abuse. Symptoms of this type of vasculitis include vision loss, memory problems, loss of balance and seizures.

What it feels like: This pain is typically sudden and is a persistent, severe pain. It can also be pulsating, and felt just on one side of the head or on the whole head.

How to treat: These symptoms should be assessed urgently in a hospital setting. Doctors will likely order an MRI, CT scan and/or angiogram to visualize the blood vessels and guide treatment and prevent further complications like brain ischemia and stroke. Treatment involves the administration of high-dose corticosteroids to reduce swelling.

4. Ear infection

An ear infection on the left side may cause a headache in this area. Other possible symptoms include fever and ear discharge.

What it feels like: The pain felt in the ear can spread to the side of the head, in the area around the head, as well as the jaw and neck. It is often described as sharp or stabbing.

How to treat: You are advised to consult a family doctor or ENT specialist if you suspect you have an ear infection. Treatment usually involves the use of medications like antibiotics and analgesics. Check-out other ways you can relieve ear pain at home.

5. Tooth infection

When tooth infections occur on the left side of the mouth, pain can radiate to the areas around the affected teeth and to the head.

Other common symptoms that can present with this type of headache include swollen gums, easy bleeding and, in more severe cases, fever.

What it feels like: Pain usually worsens when touching the affected tooth or with drinking hot or cold drink. This pain can be described as dull, but can also be sharp, and radiates from the tooth to other areas of the head, as teeth share several nerve pathways with other nerves in the head.

How to treat: If you think you may have a tooth infection, you should see your dentist for assessment and treatment as necessary. Depending on the severity, treatment may involve the use of antibiotics or even the extraction of the affected tooth. In the meantime, learn about how you can relief tooth pain at home.

6. Temporal arteritis

Temporal arteritis is an inflammation of the blood vessels. When vessels on the left side of the head are affected, it can cause symptoms like a left side headache, transient vision loss and difficulty chewing.

This pain tends to worsen with palpation, which can make common tasks like brushing you hair or sleeping on that side more difficulty. Other symptoms may include fever and general malaise.

What it feels like: This pain is typically felt in the temples, and is severe, persistent and burning. It can be throbbing or pulsating, and/or feel like pressure within the temples.

How to treat: If you suspect you may have temporal arteritis, you should see a rheumatologist for assessment. If confirmed, treatment with medications (like oral corticosteroids) can be used to manage headache and prevent worsening.

7. Temporomandibular joint (TMJ) disorder

TMJ disorder is characterized by abnormality in the functioning of the jaw joint, which can affect jaw movements and cause significant pain. TMJ disorder that affects the left side of the face can cause pain that radiates the left ear, temple and left side of the head. This pain is commonly felt when moving the jaw from speaking, eating or drinking.

What it feels like: This pain is often described as a dull or aching pain that starts in the TMJ but radiates to the temples or neck on the affected side.

How to treat: If you suspect you may have a left-sided headache caused by TMJ on the left side of the face, you should see a dentist or orthopedic surgeon. Many times, this condition can be managed with analgesic medication, and physiotherapy, while more serious cases may require surgery. Read more about TMJ treatment options that your doctor may consider.

8. Glaucoma

Glaucoma that develops in the left eye can sometimes cause sudden pain on the left side of the head, especially in the area of the affected eye. Along with a left-sided headache, this condition can also lead to symptoms like redness in the eye, blurred vision, nausea and vomiting.

What it feels like: This pain is often described as a deep and aching sensation around the eyes, although it can radiate to the forehead, temples or side of the head.

How to treat: You are advised to consult an ophthalmologist if you suspect you may have glaucoma. Treatment is aimed at preventing vision loss, and may involve the application of eye drops to reduce pressure in the eye and even surgery.

9. Tumors

Although they are rare, brain tumors can also cause left side headaches in some cases. Other symptoms will usually emerge, like seizures, weakness in certain areas of the body, nausea, vomiting and episodes of temporary vision loss. Check out the brain tumor symptoms that can occur on the left side of the brain.

The pain tends to be worse in the morning, and when lying down, coughing or with exerting force. Learn more about general cancer symptoms that you shouldn’t ignore.

What it feels like: This pain can be localized to just the area of the tumor or felt on the entire head. It is often described as a dull or pressure-like sensation.

How to treat: If you suspect a brain tumor, you should see your doctor for thorough imaging tests, like CT and MRI. If confirmed, the headache will generally improve when the tumor is treated. Treatment may include surgery and chemotherapy.

10. Stroke

A stroke can cause a headache on the left side of the head, especially when the affected areas of the brain include regions that process pain. Headache may appear around the same time as neurological changes like weakness, difficulty speaking, facial drooping, or sudden vision problems.

Read more about what causes a stroke and how it presents.

What it feels like: This type of headache may be moderate to severe and can appear suddenly. Pain can feel unusual or intense compared to past headaches and may occur together with neurological symptoms.

How to treat: A stroke is a medical emergency that requires immediate hospital care. Treatment typically involves brain imaging and interventions aimed at restoring blood flow or preventing further damage, such as thrombolytic medication or endovascular procedures. Analgesics may be used for pain control once the stroke is stabilized.

11. Aneurysm

A brain aneurysm, especially when it leaks or ruptures, can cause a severe headache on the left side of the head. Sometimes, an unruptured aneurysm may also cause localized pain if it compresses structures on one side.

What it feels like: This pain is often sudden and extremely intense, reaching peak severity within seconds. It is frequently described as the worst headache of one’s life and may appear with nausea, neck stiffness, vomiting, confusion, or seizures.

How to treat: A suspected aneurysm requires urgent assessment in the emergency department. Treatment may include surgical clipping or endovascular coiling to secure the aneurysm, as well as hospital monitoring to prevent complications. Analgesic medication is typically used as part of supportive care.

12. Tension headache

A tension headache can sometimes be felt more intensely on the left side, even though this type of headache commonly affects both sides of the head. This type of headache is often associated with muscle tension, stress, or poor posture.

What it feels like: The pain is usually described as a dull, tight, or pressure-like sensation, similar to a band around the head. It may last anywhere from minutes to several days and is generally not worsened by routine physical activity.

How to treat: Treatment often involves rest, stress management, and simple pain relievers such as acetaminophen or ibuprofen. Additional measures like relaxation techniques, posture correction, or physiotherapy may help reduce muscle tension and prevent recurrence.

13. Sinus infection

A sinus infection on the left side can cause a headache in the area overlying the left cheek, forehead, eye, or upper teeth. This happens when inflammation or blockage in the sinus cavities increases pressure on one side of the face.

What it feels like: Pain is often described as pressure or fullness on one side of the forehead, around the eye, or along the cheek. It may worsen when bending forward and can be accompanied by nasal congestion, a runny nose, or a reduced sense of smell. Read more about sinus infection symptoms and how they can present.

How to treat: Most sinus infections improve with rest, fluids, analgesics, and nasal saline irrigation. Intranasal corticosteroid sprays may help reduce inflammation. Antibiotics for sinus infections are typically reserved for cases with persistent symptoms, double worsening, or severe bacterial features, as assessed by a doctor.

When to see the doctor

You should consult a doctor if you experience any of the following:

Frequent or worsening headaches with no clear cause or past history
Sudden, severe headache that peaks within seconds (thunderclap headache)
Neurological symptoms like weakness, seizures, fainting, or confusion
Vision changes such as blurred or double vision, or temporary vision loss
Headaches triggered or worsened by lying down, coughing, or physical effort
Headaches associated with fever, stiff neck, or jaw pain while chewing
A history of cancer or new headaches after age 50

In these cases, tests like MRIs or CTs may be ordered to rule out serious conditions, like brain tumors or vascular inflammation. Results will typically guide treatment, which will be determined by the doctor.

FAQs about left-sided headaches

1. Why do I only get headaches on the left side of my head?

Some headaches tend to be lateralized due to underlying neurological or vascular patterns. Migraines, cluster headaches, and certain neuralgias may affect one side of the head due to the way nerves and vessels are structured and stimulated.

2. Are left-sided headaches more serious?

Not necessarily, but if a headache on the left side is accompanied by red flag symptoms—such as weakness, sudden intensity, vision loss or altered consciousness—it may signal a more serious condition requiring medical evaluation.

3. How long do left-sided headaches last?

It depends on the cause. Migraines may last 4 to 72 hours, cluster headaches 15 to 180 minutes, tension-type headaches 30 minutes to 7 days, and neuralgias only a few seconds. Persistent pain over weeks may suggest a chronic or secondary cause.

4. Can stress cause left-sided headaches?

Yes. Stress is a known trigger of migraines and tension-type headaches, both of which can present as unilateral pain depending on muscle tension or nerve involvement.

5. What tests are done for headaches on the left side of the head?

Depending on your symptoms, doctors may order a CT, MRI, or angiography. In some cases, blood tests or a lumbar puncture may be needed to assess for infection or inflammatory conditions like temporal arteritis.

Headache on Left Side of Head: 13 Causes, Symptoms & Treatment